Furnace for water-tube steam-boilers.



N0. saunas. Patented Jan; 14, 1902.

W. C. WALLACE. FURNACE FOR WATER TUBE STEAM BOILERS.

(Application filed Mar. 29, 1901.)

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W. C. WALLACE.

FURNACE FOR WATER TUBE STEAM BOILERS.

(Application filed Mar. 29. 1901.

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(No Model.)

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FURNACE FOR WATER TUBE STEAM BOILERS.

(Application filed Mar. 29, 1901.)

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(Application filed Mar. 29, 1901.]

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N0. 69|,089. Patented Ian. I4, I9 D2. W. C. WALLACE.

FURNACE FOR WATER TUBE STEAM BOILERS.

(Application filed Mar. 29, 1901.) (No Model.)

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NITE STATES arnnr WILLIAM CARLILE WALLACE, OF SHEFFIELD, ENGLAND, ASSIGNOR OF ONE- .HALF TO JOHN BROWN 65 COMPANY, LIMITED, OF SHEFFIELD, ENGLAND.

FURNACE FOR WATER-TUBE. STEAM BOILERS.

SPECIFICATION forming part of Letters Patent No. 691,089, dated January 14, 1902.

Application filed March 29, 1901.

T at whom, it may concern:

Be it known that LWILLIAM OARLILE WAL- LACE, engineer, a subject of the King of Great Britain and Ireland, residing at Atlas "Works,

Sheffield,in the countyof York, England, have invented certain new and useful Improvements in or Connected with the Furnaces of ater-Tube Steam-Boilers; and I do hereby declare the following to be a full, clear, and

lo exact description of the invention,such as will enable others skilled in the art to which it appertains to make and use the same.

My invention consists in improvements in or connected with water-tube steam-boilers whereby induced draft can be applied to the furnaces of such boilers.

The boilers and furnaces to which my invention can be applied are, for example, such as are known as the fBabcock'dt \Vilcox, the

' Bel1evi1le,the Necla use, and the Stirling boilers; but its application is not limited to these.

In carrying out this invention means are provided whereby the induced draft is employed so as to effect practically complete combustion of the fuel without the aid of a specially constructed combustion chamber, thus increasing the efliciency of the boiler, economizing the use of'fuel, and preventing 0 the formation and escape of black smoke.

The draft is induced by means of an air-current-inducing device, such as a fan or fans, placed in the uptake or at the base of the chimney or in other convenient position be 5 tween the boiler and the chimney, and an airheating device is employed whereby the induced draft of air for combustion is before entering the furnace heated by the escaping hot products from the furnace and then dis- 4o tributed in thin streams over the burning fuel,'so as to mix with the products of combustion arising therefrom in such manner as to cause their complete combustion to take place before entering among or between the water-tubes of the boiler. The air-heater may be of any suitable description. For example, it may consist of a collection of tubes in a casing, the waste products of combustion from the furnace to the chimney passing through or around these tubes and the enterto indicate similar parts in all the figures.

Serial No. 53.460. (No model.)

ing air for supply to the furnace passing in contact with the other surfaces of the tubes,

or the air may be wholly or in part heated by passing thro ugh narrow spaces between plates with an air space between, and these may be arranged to constitute the sides, ends, and top casings of the boiler or one or more of them. The air thus heated is carried by ducts or passages extending along the sides and back or in other convenient position to a distribut- 6o ing-chamber arranged in any con veniient position toallowofconnection by suitable ducts or passages with passages formed in the wall or walls of the furnace, (with or Without metal linings,) other walls with passages therein being provided in the case of large fire-grates, which walls divide the fire-grate surface at intervals and run the length of the furnace, this Wall or these Walls having perforated bricks or slits in themby which the heated air cs capes above the fuel. Similar passages and slits or perforations may, if desired, also in some kinds of settings be formed in the bridge- Walls. Passages may be also provided for conducting the heated air'into the ash-pit beneath the grate, the passages for the heated air to above and below the grate being provided with valves for regulating the supply of air to each or either, as desired.

The accompanying drawings illustrate examples of arrangements whereby thisinvention may be carried into effect; but the in- Vention is not limited to the precise arrangements shown.

Figure 1 of the accompanying drawings is a longitudinal vertical section of a stationary water-tube boiler and furnace provided with improvements according to this invention. Fig. 2 is a front elevation of the same, partly in section; and Fig. 3 is a horizontal section on the line 3 3, Fig. 1. Fig. 4 shows, partly in front elevation and partly in transverse section on the line 4 4, Fig. 5, a marine water-tube boiler of the Babcock dz Wilcox type provided with improvements according to 5 this invention, Fig. 5 beinga longitudinal section through one of the fire-doors of thefurnace shown in Fig. 4.

The same letters of reference are employed IOO - Referring to Figs. 1, 2, and 3, the draft is induced by means of a fan A or fans at the back of the boiler B and furnace O and between the uptake D and the chimney E, as shown. The outlet from the fan A is connected by a pipe or passage F with the chimney E, and the entrance to the said fan is in communication by a passage G with the uptake D. In the said uptakeis formed a chamber H, having agroup or groups of tubes I, through which the products of combustion from the furnace pass, as shown by full arrows, into the fan and are discharged by the said fan into the chimney. Air is admitted to the chamber H by openings K and caused to pass, as shown by dotted arrows, therethrough in contact with the tubes I, and thence through pipes or passages L, extending along the sides of the furnace, into chambers M, situated behind the fire-bridge N. The air in its passage by impinging against the tubes I becomes heated by the products of combustion passing through the said tubes. It is obvious, however, that the arrangement may be such that the products of combustion may pass in contact with the exteriors of the tubes and the air pass through the said tubes. The chambersM communicate through openings ct with the ash-pit O of the furnace and through other openings 17 with passages c in the main walls P of the fireplace and in hollow-walls P, which divide the fire-grate surface at intervals. In the chambers M are arranged valves d, by means of which the openingsb can be closed, so as to direct the whole of the heated air into the ash-pit O, or the openings at can be closed, so as to direct the whole of the air into the passages c in the main walls P of the fireplace and in the divi-' sion-walls P, or the said valve or valves (1 may be adjusted so as to direct some of the heated air into the ash-pit and some into the said passages c. The division-walls P may be built of fire-bricks and be lined or not with metal. In the opposite sides of the walls P are perforations 0, through which the heated air passes in streams over the fuel, the action of the fan A being such that while exhausting the products of combustion from the furnace it also induces air-currents through the heating devices and the distributing arrangements M andP into the furnace, whereby a practically-complete combustion of the gases rising from the fuel is effected before the products pass between the water-tubes of the boiler. If desired, air-passages similar to those in the walls P and P of the furnace may be provided in the fire-bridge N, so that the heated air can be directed over the fuel from the back as well as from the sides of the furnace, and means may be provided for admitting cold air under the fire-bars in the ordinary manner.

The arrangement of the air-passages will of course be varied according to the construction and arrangement of the water-tube boiler to which the invention is applied. For example, in Figs. 4 and 5, which show the invention applied to a marine Water-tube boiler of the Babcock & Wilcox type, the duct or passage L for conducting the air from the airheating device H into the furnace extends along both sides of the furnace and communicates with a passage or chamber M at the back of the furnace and also with passages M extending across the front of the furnace, except where the fire-doors are situated. The heated air passes from the passage L into the furnace through perforations e in the two side Walls P and from the passage or chamber M through similar perforations in the back Wall M and also through perforations e in baffleplates P constituting one wall of the passages M at the front of the furnace. By this arrangement heated air can be directed into the fireplace abovethe fuel from the front and back as well as from the sides of the furnace,

and thus be distributed over the whole of the fuel. The intermediate walls P (shown in Figs. 1, 2, and 3) are omitted from the arrangement Figs. 4 and 5, as these intermediate walls are required only in the case of large grate-surfaces and are for the purpose of distributing the heated air more uniformly over the whole of the fuel.

I do not limit myself to the arrangement of the air-heating device in the uptake as hereinbefore described, as it may be varied. For

example, a casing for the boiler may be formed of double plates with a space between the plates and an opening or openings for the admission of air to the said space, which air will be heated by the radiated heat from the boiler, and the said space may be in communication with the air-distributing device M, so that the said heated air will be drawn into the furnace by the fan or fans, as in the arrangement illustrated by the drawings.

Having now particularly described and ascertained the nature of this invention and in what manner the same is to be performed, I declare that what I claim is- 1. The combination with a water tube boiler, havinga combustion-chamber or fireplace in which the products of combustion ascend vertically in contact with the watertubes above said chamber, of adevice for heating air, hollow side walls having perforations discharging air horizontally into the fireplace, passages connecting the air-heating device with the said hollow perforated walls, and a fan or fans situated between the furnace and the chimney, by means of which fan or fans the products of combustion are drawn from the furnace and heated air in streams is drawn through the perforations in the hollow side walls to the fireplace, substantially as described.

2. The combination with a water tube boiler having a combustion-chamber or fireplace in which the products of combustion ascend vertically in contact with the water-tubes above said chamber, of a device for heating the fireplace, whereby the heated air is disair, perforated Walls at the sides and back of tributed horizontally over the fuel from the the furnace and perforated plates in the front I sides, back, and front of the fireplace, subof the fireplace, a duct or passage, in connecstantially as and for the purpose described.

5 tion with the air-heating device, extending In testimony whereof I affix my signature 15 along both sides, the back, and partly across in presence of two Witnesses. the front of the fireplace and horizontally com- WILLIAM CARLILE WVALLA'OE. m unicating with the interior of the fireplace Witnesses:

through the perforations in the side Walls of I EDWD. GEO. DAVIES, 10 the furnace and in the plates at the front of l G. F. TYSON. 

